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North Pacific climate patterns influence El Niño occurrences

Another attempt to shed light on this recurring but tricky to predict climate phenomenon.

For decades, scientists have observed the phenomena known as El Niño and La Niña, says Phys.org. Both significantly impact the global climate and both pose a puzzle to scientists since they’re not completely understood.

Now, a new study clarifies some of the obscurity surrounding El Niño and La Niña, which together are called the El Niño Southern Oscillation (ENSO).

This new study examines ENSO frequency asymmetry during the phases of the Pacific Decadal Oscillation (PDO), a climate pattern in the North Pacific.

Previous studies have investigated the relationship between ENSO and PDO, but none have examined whether the warm (positive) and cool (negative) phases of PDO in the North Pacific influence the frequency of ENSO events in the tropical Pacific. “For the first time,” said Prof. ZHENG Fei from the Institute of Atmospheric Physics, Chinese Academy of Sciences, and co-author on the study, “we have quantitatively demonstrated that El Niño is 300 percent more frequent than La Niña in positive PDO phases, and 58 percent less frequent in negative PDO phases.”

The findings were published in Advances of Atmospheric Sciences and selected as the cover article of Issue 5.

To arrive at their findings, the researchers used observational data and the output of 19 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). “By adopting the observations and CMIP5 climate model simulations,” said Zheng, “we had an opportunity to explore how PDO modulates the occurrence of ENSO.” This type of exploration meets an increasing need today, which is for scientists to better understand the mechanisms that affect the occurrence of ENSO.

While all the answers surrounding these events aren’t known, the effects of ENSO are well understood. When sea surface temperatures are warmer or cooler than normal in the equatorial Pacific Ocean, weather patterns around the world are impacted. Everything from pressure systems to wind and precipitation can be influenced by ENSO, including the supply of water in a region since it can cause moisture extremes.

The answer is that both the El Nino component of the ENSO and PDO are driven by the same underlying mechanism i.e. a combination of the solar sunspot cycle and the lunar tides.

PDO (~ 60 years)

An equilibrium tide of +/- 7 mm is induced in the surface of the Pacific ocean by the 18.6 Lunar Nodal Cycle (LNC). The displayed figure shows that distribution of this equilibrium tide looks very much like the pattern exhibited by the PDO. The maximum latitude of the Moon from the Earth’s Equator oscillates up and down between 18 1/2 and 28 1/2 degrees over an 18.6 period known as the LNC cycle. This is caused by the 5.0 degree tilt of the Moon with respect to the Ecliptic (plane of the solar system).

ENSO (~ 4.5 years)

It takes 62 years for the Perigean New/Full moon cycle to realign with the seasons. The Perigean New/Full Moons are responsible for trigger moderate to strong El Nino events.

Lunar Connection:

The closest whole divisor of 62.0 years to 18.6 years is 20.66667 years. Hence, the 62.0-year and 18.6-year cycles re-align once every 186.0 years:

(18.6 x 20.666667) / (20.666667 – 18.6) = 186.0 years

i.e. three 62.0-year cycles = ten 18.6 year cycles = 186.0 years.

This roughly 8.0 years more than 178.7 year Jose Cycle.

Solar Connection:

Conjunctions (i.e. alignments) between Venus and the Earth take place every 1.6 years. It takes five these conjunction for the alignment of Venus and the Earth to occur at the same point in Earth’s seasonal calendar. 5 x 1.6 = 8.0 years.

The conjunctions of Jupiter and Saturn every 19.858 years produces a tres-foil loop-like pattern in the motion of the Sun about the centre-of-mass of the solar system (i.e. the Barycentre). It takes three of these loops by the Sun for it to move once about the centre of the solar system with respect to the stars. 3 x 19.858 = 59.574 years and the whole Barycentric motion of the Sun repeats its self roughly three of these ~ 60 years periods i.e. 3 x 59.574 = 178.72 years. This period is known as the Jose Cycle.

[N.B. This is 8 times the 22.34 year Hale Cycle, 8 x 22.34 = 178.72 years]

The following post at my blog investigates the close connection between the North Pacific Index (NPI) and the conjunctions of Jupiter and Saturn.

You are correct, however at this stage we have no firm idea about which of the two mechanisms (i.e. lunar or solar) dominates as the driving mechanism at the time scales of the PDO (~ 60 years) and ENSO (~ 4.5 years).

I tossed the ~ 8 year difference in as a possible seed-idea for further investigation as it might involve the planets – Given that it is actually 7.3 years it may not have been such a good move.

I have a feeling (at this stage that’s all that is) that the lunar and solar mechanisms slowly get out of synchronization with each other over time , possibly producing the ~ 1150/2300/4600 year long- term warming cycle that we see in the climate.

e.g. the beat period between the 186 year lunar cycle and the 178.72 year Jose cycle is:

(178.72 x 186) / (186.0 – 178.72) = 4566 years ~ 4600 years.

The actual dates upon which the re-alignments of Uranus and Neptune are re-synchronized with the re-alignments of Jupiter and Saturn are:

As you can see, there is an oscillation between a period of 2224
years and 2403.7 yrs, giving a full mean repetition period (where all the
Jovian planets are lined up on the same side of the Sun) of ~4627.7
yrs. Thus the Jovian planets reset their alignments roughly once every
26 Jose cycles = 26 x 178 yrs = 4628 yrs.

Which is not far off the beat period between the Jose Cycle and the 186-year lunar cycle.

You are correct, however at this stage we have no firm idea about which of the two mechanisms (i.e. lunar or solar) dominates as the driving mechanism at the time scales of the PDO (~ 60 years) and ENSO (~ 4.5 years).

I tossed the ~ 8 year difference in as a possible seed-idea for further investigation as it might involve the planets – Given that it is actually 7.3 years it may not have been such a good move.

I have a feeling (at this stage that’s all that is) that the lunar and solar mechanisms slowly get out of synchronization with each other over time , possibly producing the ~ 1150/2300/4600 year long- term warming cycle that we see in the climate.

e.g. the beat period between the 186 year lunar cycle and the 178.72 year Jose cycle is:

(178.72 x 186) / (186.0 – 178.72) = 4566 years ~ 4600 years.

The actual dates upon which the re-alignments of Uranus and Neptune are re-synchronized with the re-alignments of Jupiter and Saturn are:

As you can see, there is an oscillation between a period of 2224
years and 2403.7 yrs, giving a full mean repetition period (where all the
Jovian planets are lined up on the same side of the Sun) of ~4627.7
yrs. Thus the Jovian planets reset their alignments roughly once every
26 Jose cycles = 26 x 178 yrs = 4628 yrs.

Which is not far off the beat period between the Jose Cycle and the 186-year lunar cycle.

This comes from the lunar precession link above. The full period is 339 Metonic cycles = 6441 trop. yrs.
SM and LAC are exact multiples of 104, all others are 7 short of an exact multiple of 104, e.g:
5713 FMC = 55 * 104, -7
6441 TY = 62 * 104, -7
These all match up to within half a day of the published values (i.e. < 0.5 of a day in 6441 years).